Laser ablation of ternary As-S-Se glasses and clusters analysisby time of flight mass spectrometry

Ternary chalcogenide As-S-Se glasses, important for optics, computers, material science and technological applications are often made by pulsed laser deposition (PLD) technology but the plasma composition formed during the process is mostly unknown. Therefore, the formation of clusters in a plasma plume from different glasses was followed by Laser Desorption Ionization (LDI) or Laser Ablation (LA) Time of Flight Mass Spectrometry (TOF MS) in positive and negative ion modes. LA of glasses of different composition leads to the formation of a number of binary AspSq, AspSerq and ternary AspSqSer single charged clusters. Series of clusters with the ratio As:chalcogen = 3:3 (As3S3+, As3S2Se+, As3SSe2+), 3:4 (As3S4+, As3S3Se+, As3S2Se2+, As3SSe3+, As3Se4+), 3:1 (As3S+, As3Se+), and 3:2 (As3S2+, As3SSe+, As3Se2+) being formed from both bulk and PLD deposited nano-layer glass was detected. The stoichiometry of AspSqSer clusters was determined via isotopic envelope analysis and computer modeling. The structure of the clusters is discussed.